What are the bells and telephone designs in the elevator for?

The pattern of the alarm bell indicates that when a passenger is trapped in the elevator, pressing this button will turn on the alarm bell, and rescuers can accurately find the position of the elevator according to the direction of the alarm bell to carry out rescue; The telephone mode means that when the elevator breaks down and is trapped, you can get in touch with the rescuers through the emergency telephone and come to the rescue work as soon as possible.